Connection terminal, connection device, method for manufacturing the device, motor using the device, and compressor using the motor and blower using the motor

ABSTRACT

Connection terminal ( 10 ) according to the present invention includes a tab part and not smaller than four pinching plates ( 12 ) that hold an aluminum electric wire. Pinching plates ( 12 ) each include first slit ( 13 ) and contact surfaces ( 14 ). First slit ( 13 ) has a first open end located in one side of the slit, and a first tip located in the other side. The aluminum electric wire is inserted into first slit ( 13 ). Contact surfaces ( 14 ) are in contact with the aluminum electric wire that is press-fitted into first slit ( 13 ). A contact area in which contact surfaces ( 14 ) are in contact with a core wire is an area of 100% to 200% of a radial cross-sectional area of the core wire.

TECHNICAL FIELD

The present invention relates to connection terminals used for aluminumelectric wires, connection devices including the connection terminals,methods for manufacturing the connection devices, motors using theconnection devices, and compressors using the motors and blowers usingthe motors.

BACKGROUND ART

Conventionally, electrical apparatus such as transformers, reactors, andmagnetrons have employed insulated electric wires made of aluminum astheir core wires, in order to reduce weight of the electrical apparatus.Hereinafter, an insulated electric wire in which its core wire is madeof aluminum and the outer peripheral surface of the core wire is coatedwith an insulating coating, is referred to as an aluminum electric wire.Aluminum has characteristics that it tends to suffer a deformation dueto a creep phenomenon. Hereinafter, the deformation due to the creepphenomenon is referred to as the creep deformation. In the aluminumelectric wire, its stress is relaxed when the creep deformationprogresses. Hereinafter, such the relaxation of the stress caused by thecreep deformation is referred to as the stress relaxation.

Concerning connections of aluminum electric wires, there have beenproposals to address the creep deformation of aluminum, as shown inPatent Literatures 1 and 2.

In Patent Literature 1, a configuration is proposed in which a crimpterminal has a groove formed in a crimping part thereof, with the crimpterminal being connected to the aluminum electric wire. In PatentLiterature 1, the formation of the groove is expected to address thecreep deformation. Note that the crimp terminal referred in PatentLiterature 1 corresponds to the connection terminal according to thepresent application.

In Patent Literature 2, the proposed connection terminal is such that aplurality of strain regions is formed in a plate-like part included inthe connection terminal. The plate-like part is formed by folding acrimping part included in the connection terminal. In Patent Literature2, the formation of the plurality of the strain regions is expected toaddress the creep deformation.

CITATION LIST Patent Literatures

-   Patent Literature 1: Japanese Patent No. 4550791-   Patent Literature 2: Japanese Patent Unexamined Publication No.    2011-192637

SUMMARY OF THE INVENTION

A connection terminal according to the present invention is used for analuminum electric wire which includes a core wire and an insulatingcoating which covers the outer peripheral surface of the core wire. Theconnection terminal includes a tab part and not smaller than fourpinching plates which hold the aluminum electric wire.

The pinching plates each include a first slit and contact surfaces. Inthe first slit, a first open end is located in one side of the slitwhile a first tip is located in the other side. Moreover, the aluminumelectric wire is press-fitted into the first slit. The contact surfacesare in contact with the aluminum electric wire that is press-fitted intothe first slit. The contact area, in which the contact surfaces are incontact with the core wire, is an area of 100% to 200% of the radialcross-sectional area of the core wire.

Moreover, a connection device according to the present invention is usedfor an aluminum electric wire that includes a core wire and aninsulating coating that covers the outer peripheral surface of the corewire. The connection device includes a connection terminal and a holdingpart.

The connection terminal includes a tab part and not smaller than four ofpinching plates which hold the aluminum electric wire. The holding partincludes cavities into which the connection terminals are inserted.

The pinching plates each include a first slit and contact surfaces. Inthe first slit, a first open end is located in one side of the slit,while a first tip is located in the other side. Moreover, the aluminumelectric wire is press-fitted into the first slit. The contact surfacesare in contact with the aluminum electric wire that is press-fitted intothe first slit. The contact area, in which the contact surfaces are incontact with the core wire, is an area of 100% to 200% of the radialcross-sectional area of the core wire.

The cavity includes a wall surface and a second slit. The wall surfacesurrounds at least the pinching plates of the inserted connectionterminal. The second slit is formed such that, in the wall surface, asecond open end is located in one side of the slit while a second tip islocated in the other side, at a location facing the first slit. In thesecond slit, the second open end is larger in a slit width than thesecond tip.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an elevational view of a connection terminal according to afirst embodiment of the present invention.

FIG. 2 is a side-elevational view of the connection terminal accordingto the first embodiment of the invention.

FIG. 3 is a bottom plan view of the connection terminal according to thefirst embodiment of the invention.

FIG. 4 is an enlarged view of a principal part of the connectionterminal according to the first embodiment of the invention.

FIG. 5 is a cross-sectional view taken along line 5-5 in FIG. 4.

FIG. 6 is a characteristic graph illustrating a relation between a wirediameter of an aluminum electric wire and a ratio of a contact area to across-sectional area of a core wire, according to the first embodimentof the invention.

FIG. 7 is a bottom plan view of another connection terminal according tothe first embodiment of the invention.

FIG. 8 is a bottom plan view of another pinching plate included in theconnection terminal according to the first embodiment of the invention.

FIG. 9 is a bottom plan view of further another pinching plate includedin the connection terminal according to the first embodiment of theinvention.

FIG. 10 is an illustrative view of an operation in which an aluminumelectric wire is press-fitted into another connection terminal,according to the first embodiment of the invention.

FIG. 11 is an illustrative view of the operation in which the aluminumelectric wire is press-fitted into the another connection terminal,according to the first embodiment of the invention.

FIG. 12 is an illustrative view of an operation in which an aluminumelectric wire is press-fitted into the another connection terminal,according to the first embodiment of the invention.

FIG. 13 is an illustrative view of the operation in which the aluminumelectric wire is press-fitted into the another connection terminal,according to the first embodiment of the invention.

FIG. 14 is a perspective view of a connection device according to asecond embodiment of the present invention.

FIG. 15 is a perspective view of a principal part of the connectiondevice according to the second embodiment of the invention.

FIG. 16 is a cross-sectional perspective view of a cavity which isincluded in the connection device according to the second embodiment ofthe invention.

FIG. 17 is an elevational view of the cavity that is included in theconnection device according to the second embodiment of the invention.

FIG. 18 is a cross-sectional perspective view of a principal part of theconnection device according to the second embodiment of the invention.

FIG. 19 is another cross-sectional perspective view of the principalpart of the connection device according to the second embodiment of theinvention.

FIG. 20 is a cross-sectional view taken along line 20-20 in FIG. 19.

FIG. 21 is a plan view of a connection terminal which is included in theconnection device according to the second embodiment of the invention.

FIG. 22 is a plan view of a cavity which is included in the connectiondevice according to the second embodiment of the invention.

FIG. 23 is a plan view illustrating a state where the connectionterminal is inserted into the cavity included in the connection deviceaccording to the second embodiment of the invention.

FIG. 24 is a perspective view of another connection terminal which isincluded in the connection device according to the second embodiment ofthe invention.

FIG. 25 is a plan view of another cavity which is included in theconnection device according to the second embodiment of the invention.

FIG. 26 is a perspective view of a different connection terminal whichis included in the connection device according to the second embodimentof the invention.

FIG. 27 is a plan view of a different cavity which is included in theconnection device according to the second embodiment of the invention.

FIG. 28 is a flowchart illustrating a method for manufacturing aconnection device according to a third embodiment of the presentinvention.

FIG. 29 is an illustrative view of an assembly operation of theconnection device according to the third embodiment of the invention.

FIG. 30 is a flowchart illustrating another method for manufacturing theconnection device according to the third embodiment of the invention.

FIG. 31 is a cross-sectional perspective view of a principal part of theconnection device according to the third embodiment of the invention.

FIG. 32 is another cross-sectional perspective view of the principalpart of the connection device according to the third embodiment of theinvention.

FIG. 33 is a characteristic graph illustrating characteristics of anincremental quantity of contact resistance with respect to the number ofinsertion-removal cycles of a flat connection terminal into and from theconnection device according to the third embodiment of the invention,with the flat connection terminal being fitted into the connectiondevice.

FIG. 34 is a perspective assembly view of a motor according to a fourthembodiment of the present invention.

FIG. 35 is a perspective assembly view of a stator which is included inthe motor according to the fourth embodiment of the invention.

FIG. 36 is a perspective assembly view of another connection devicewhich is included in the motor according to the fourth embodiment of theinvention.

FIG. 37 is a cross-sectional view of a compressor according to thefourth embodiment of the invention.

FIG. 38 is a cross-sectional view of a blower according to the fourthembodiment of the invention.

FIG. 39 is a characteristic graph illustrating characteristics ofcontact resistance with respect to the number of cycles of a thermalshock test which compares the connection device according to the fourthembodiment of the invention with comparative ones.

FIG. 40 is a characteristic graph illustrating characteristics of thecontact resistance before and after a vibration test which compares theconnection device according to the fourth embodiment of the inventionwith the comparative ones.

DESCRIPTION OF EMBODIMENTS

The present invention is intended to suppress progress of a creepdeformation in electrical apparatus that employs an aluminum electricwire, through the use of a connection terminal and a connection deviceincluding the connection terminal according to each of embodiments ofthe invention to be described later.

Moreover, the connection terminal according to the embodiment of theinvention and the connection device including the connection terminal,can suppress a loss of stress on the connection terminal to hold thealuminum electric wire, with the loss resulting from the creepdeformation.

Accordingly, the stress with which the connection terminal holds thealuminum electric wire is securely maintained.

As a result, the use of the connection device according to theembodiment of the present invention allows a highly reliable motor. Themotor can be used in a compressor and a blower.

This means that conventional connection terminals involve the followingsubjects to be improved.

That is, according to Patent Literature 1, a specialized jig is neededfor crimping a crimp terminal. In addition, in Patent Literature 1, aninsulating cap is needed to cover a crimping part for securelymaintaining the part's insulation to other conductive bodies.

Moreover, the crimp terminal described in Patent Literature 1 requiresthat the connected crimping part is fixed to be immobilized againstvibrations. For example, in the case of a motor, the crimping part isfixed to such as a coil end part of a winding formed of the aluminumelectric wire. The need for such the process leads to low productivity.

These reasons require additional manufacturing facilities, componentcounts, and working man-hours, in accordance with Patent Literature 1.In addition, these reasons become factors responsible for increasedcosts as well.

The connection terminal is also used in a motor for driving such as acompressor and a blower. The motor for driving the compressor is used inenvironments with strong vibrations and wildly-varying temperatures.When the motor, such as one used in the compressor, is used underparticularly difficult conditions in terms of vibration and temperaturevariation, the creep deformation of the aluminum electric wire becomeseasier to progress. This is because, when the fixation is madeinsufficiently between the connection terminal and a fixing member forfixing the connection terminal, the connection terminal will moverelative to the fixing member. Accumulation of small movements isconsidered to help the creep deformation progress. The progress of thecreep deformation causes a loss of stress on the connection terminalrelative to the aluminum electric wire.

Under such the difficult conditions, when using the connection terminaldescribed in Patent Literature 2, the creep deformation progresses tocause a stress relaxation. The occurrence of the stress relaxationbetween the aluminum electric wire and the connection terminal, resultsin a decrease in joint strength between the aluminum electric wire andthe connection terminal. The decrease in the joint strength, in turn,increases contact resistance of the joining portion between the aluminumelectric wire and the connection terminal. The increase in the contactresistance is thought to cause an unexpected malfunction such as a haltof operation of the electrical apparatus which uses the connectionterminal. Consequently, reliability is low in the electrical apparatusin accordance with Patent Literature 2.

Accordingly, in the case where the aluminum electric wire is used in themotor for use in the compressor, blower, etc., a highly reliableconnecting method which provides a connection capable of withstandingharsh service environments is desired for the connecting portion of thealuminum electric wire.

Hereinafter, descriptions will be made regarding a connection terminalexhibiting particularly outstanding advantages when used with analuminum electric wire, and regarding a connection device including theconnection terminal, with reference to the accompanying drawings.

In addition, a method for manufacturing the connection device will bedescribed with reference to the drawings.

Moreover, descriptions will also be made regarding a motor using theconnection device, a compressor using the motor, and a blower using themotor, with reference to the drawings.

Note, however, that each of the embodiments described hereinafter is oneexample of applications of the present invention, and does not set anylimit to the technical scope of the present invention.

First Exemplary Embodiment

A connection terminal according to a first embodiment of the presentinvention will be described with reference to FIGS. 1 to 13.

FIG. 1 is an elevational view of the connection terminal according tothe first embodiment of the invention. FIG. 2 is a side-elevational viewof the connection terminal according to the first embodiment of theinvention. FIG. 3 is a bottom plan view of the connection terminalaccording to the first embodiment of the invention. Using FIGS. 1 to 3,an appearance of the connection terminal according to the firstembodiment of the invention will be described.

FIG. 4 is an enlarged view of a principal part of the connectionterminal according to the first embodiment of the invention. FIG. 5 is across-sectional view taken along line 5-5 in FIG. 4. Using FIGS. 4 and5, the principal part of the connection terminal according to the firstembodiment of the invention will be described.

FIG. 6 is a characteristic graph illustrating a relation between a wirediameter of an aluminum electric wire and a ratio of a contact area to across-sectional area of a core wire, according to the first embodimentof the invention.

The connection terminal according to the first embodiment of theinvention is used for the aluminum electric wire that includes the corewire and an insulating coating which covers the outer peripheral surfaceof the core wire.

As shown in FIGS. 1 to 3, connection terminal 10 according to the firstembodiment of the invention includes tab part 11 and four of pinchingplates 12 that hold the aluminum electric wire.

Each of pinching plates 12 includes first slit 13 and contact surfaces14. First slit 13 has first open end 15 located in one side of the slitand first tip 16 located in the other side.

As shown in FIG. 4, aluminum electric wire 17 is press-fitted into firstslit 13. Contact surfaces 14 are in contact with aluminum electric wire17 press-fitted in first slit 13.

As shown in FIG. 5, the contact area between contact surfaces 14 andcore wire 17A is an area of 100% to 200% of the radial cross-sectionalarea of core wire 17A. Note that the contact area as referred herein isa total area of effective contact surfaces 18 at which contact surfaces14 are in contact, relative to the radial cross-sectional area of corewire 17A.

Further details of this are as follows.

As shown in FIGS. 1 to 3, connection terminal 10 can be formed with acopper alloy. A specific example of the copper alloy is MSP1 (MSP is aRegistered Trade Mark), a CDA alloy manufactured by Mitsubishi ShindohCo., Ltd.

Connection terminal 10 includes tab part 11. Into tab part 11, acorresponding flat connection terminal is fitted, as shown in a secondembodiment and subsequent ones to be described later.

As shown in FIGS. 4 and 5, each of pinching plates 12 has contactsurfaces 14 along first slit 13. When aluminum electric wire 17 ispress-fitted into first slit 13, insulating coating 17B is removed bycontact surfaces 14. Therefore, core wire 17A of aluminum electric wire17 becomes in contact with contact surfaces 14. Pinching plates 12 areformed of outer pinching plates 12A forming the outer shell ofconnection terminal 10 and inner pinching plates 12B disposed in theinside of connection terminal 10. At contact points 19 where core wire17A is in contact with contact surfaces 14, stresses are applied to corewire 17A from contact surfaces 14 in four directions. More specifically,as shown in FIG. 5, at each of contact points 19, the stresses areapplied toward the contact point in the directions, from contactsurfaces 14A included in outer pinching plate 12A and from contactsurfaces 14B included in inner pinching plate 12B.

That is, the stresses are applied to core wire 17A from the fourdirections. Against these stresses, aluminum electric wire 17 generatesreaction forces. The progress of the creep deformation can be suppressedwhen the stresses applied from contact surfaces 14 to aluminum electricwire 17 are moderately balanced with the reaction forces generated fromaluminum electric wire 17 to contact surfaces 14. Hereinafter, thestresses applied to core wire 17A from the four directions are referredto as the internal stresses.

FIG. 6 shows the wire diameter of the core wire and a ratio, to the corewire, of the contact area in which the contact surfaces are in contactwith the core wire.

As shown in FIG. 6, when the contact area is smaller than 100%, theconnection terminal is unable to maintain the internal stresses. Whenthe internal stresses cannot be maintained, the creep deformation of thealuminum electric wire becomes easy to progress. Therefore, the jointstrength decreases between the aluminum electric wire and the connectionterminal. The decrease in the joint strength increases the contactresistance of the joining portion between the aluminum electric wire andthe connection terminal. When the contact resistance increases to exceedan allowable value, a poor electrical connection occurs. This region isreferred to as contact-resistance increasing region 24.

On the other hand, when the contact area is larger than 200%, thestrength of the aluminum electric wire decreases. That is, when thealuminum electric wire is press-fitted into the first slit, the corewire is deformed by the contact surfaces. As a result of the deformationof the core wire, the radial cross-sectional area of the core wirebecomes small. The decrease in the radial cross-sectional area of thecore wire decreases the wire strength of the aluminum electric wire. Anexcessive decrease in the wire strength of the aluminum electric wiresometimes results in a broken wire. This region is referred to aswire-strength decreasing region 25.

As can be seen from the above description, in accordance with theconnection terminal according to the first embodiment of the presentinvention, the stresses are applied to the core wire from the contactsurfaces in the four directions at the contact points where the corewire is in contact with the contact surfaces. Against the stresses, thereaction forces are generated from the core wire to the contactsurfaces. When the stresses and the reaction forces are moderately invalance, the progress of the creep deformation can be suppressed evenunder difficult conditions. This allows the internal stresses to bemaintained.

When the contact area is in the range from 100% to 200% of the radialcross-sectional area of the core wire, it is possible to maintain thestate where the stresses and the reaction forces are moderately invalance. Therefore, the progress of the creep deformation can besuppressed, which thereby maintains the wire strength of thepress-fitted aluminum electric wire.

Note, however, that the number of the pinching plates may be not smallerthan four.

For example, as shown in FIG. 7, when six of the pinching plates 12 areused, each of the plates generates the internal stresses to thecorresponding contact point 19. Also in this case, similar functionaladvantages can be expected as long as the contact area is in the rangefrom 100% to 200%.

Next, configurations to obtain the contact area ranging 100% to 200%will be described.

FIG. 7 is a bottom plan view of another connection terminal according tothe first embodiment of the present invention. FIG. 8 is a bottom planview of another pinching plate included in the connection terminalaccording to the first embodiment of the invention. FIG. 9 is a bottomplan view of further another pinching plate included in the connectionterminal according to the first embodiment of the invention. Using FIGS.7 to 9, another embodiment will be described of the connection terminalaccording to the first embodiment of the invention.

In addition to the shape described above, the connection terminalaccording to the first embodiment of the invention is such that each ofthe contact surfaces has an angle of inclination ranging 15° to 75°relative to the direction in which the not smaller than four pinchingplates are arranged.

Further details of this are as follows.

As shown in FIGS. 3 and 5, in connection terminal 10, four pinchingplates 12 are sequentially arranged along the axial direction of thealuminum electric wire to be press-fitted. In FIG. 3, the directionindicated by the arrow is referred to as direction 23 in which thepinching plates are arranged.

Each of contact surfaces 14 has an inclination angle a ranging 15° to75° relative to direction 23 in which the pinching plates are arranged.

Table 1 shows the degree of variations in contact resistance whichoccurs between the aluminum electric wire and the contact surfaces,before and after a thermal shock test.

TABLE 1 Variations in contact resistance after a thermal shock test withrespect to inclination angle a of the contact surfaces Inclination angleα 0° 15° 30° 45° 60° 75° 90° Presence/absence of X ◯ ◯ ◯ ◯ ◯ Xvariations ◯: absence of variations X: presence of variations

The thermal shock test was carried out with the following conditions.The ambient temperature was varied from −40° C. to 120° C. One cycleconsisted of states, i.e. the state where the ambient temperature of−40° C. was kept for 30 minutes and the state where the ambienttemperature of 120° C. was kept for 30 minutes. The cycle was repeated1000 times, i.e. 1000 cycles. Incidentally, these conditions are for anaccelerated test to determine whether or not a compressor, shown in afourth embodiment to be described later, can withstand practical use.

Before and after the thermal shock test, when the variations in thecontact resistance were observed within 1 mΩ, the contact resistance isdetermined to be in “absence of variations.” On the other hand, when thevariations in the contact resistance observed exceeds 1 mΩ, the contactresistance is determined to be in “presence of variations.”

As shown in Table 1, when inclination angle α is smaller than 15°, theresult after the thermal shock test has shown that the contactresistance exhibits the variations. The reason of this is consideredthat the internal stresses cannot be maintained in the radial directionof the aluminum electric wire. That is, in the aluminum electric wire,the stress relaxation occurs due to the progress of the creepdeformation. The occurrence of the stress relaxation increases thecontact resistance between the aluminum electric wire and the connectionterminal. The contact resistance increases to exceed the allowablevalue, resulting in the poor electrical connection.

On the other hand, when inclination angle α is larger than 75°, it isconsidered that the internal stresses cannot be maintained in the radialdirection of the aluminum electric wire in the early stage of thethermal shock test. That is, in the aluminum electric wire, the stressrelaxation occurs due to the progress of the creep deformation. Theoccurrence of the stress relaxation increases the contact resistancebetween the aluminum electric wire and the connection terminal. Thecontact resistance increases to exceed the allowable value, resulting inthe poor electrical connection.

Note, however, that similar functional advantages can be expected evenwhen pinching plates 12 have other cross-sectional shapes in direction23 in which the plates are arranged, including a curved shape as shownin FIGS. 8 and 9.

Next, a case of the embodiment in which a plurality of the aluminumelectric wires is press-fitted into the connection terminal will bedescribed.

FIG. 10 is an illustrative view of an operation in which the aluminumelectric wire is press-fitted into another connection terminal accordingto the first embodiment of the invention. FIG. 11 is an illustrativeview of the operation in which the aluminum electric wire ispress-fitted into the another connection terminal according to the firstembodiment of the invention. FIG. 12 is an illustrative view of anoperation in which an aluminum electric wire is press-fitted into theanother connection terminal according to the first embodiment of theinvention. FIG. 13 is an illustrative view of the operation in which thealuminum electric wire is press-fitted into the another connectionterminal according to the first embodiment of the invention.

Using FIGS. 10 to 13, the operations will be described in which thealuminum electric wires are press-fitted into the another connectionterminal according to the first embodiment of the invention.

In addition to the shape described above, the connection terminalaccording to the first embodiment is such that the first slit has atemporarily holding part where the aluminum electric wire is temporarilyheld when the aluminum electric wire is press-fitted.

Further details of this are as follows.

As shown in FIG. 10, in connection terminal 10A, temporarily holdingpart 21 is disposed in the vicinity of first open end 15. Temporarilyholding part 21 is preferably located, in first slit 13, closer to firstopen end 15 than to first tip 16. It is only required for temporarilyholding part 21 to have a width to the extent to which the press-fittedaluminum electric wire can be held. Temporarily holding part 21preferably includes tapered parts 22 with a taper shape that aredisposed in the first tip 16 side.

Concerning the connection terminal having such the temporarily holdingpart, its functional advantages will be described through explanationsof a comparative example and a specific example.

Comparative Example

For example, two of the aluminum electric wires are press-fitted into afirst slit included in a connection terminal. For the connectionterminal without the temporarily holding part, the first slit becomes inthe state of being opened, at the stage of the first one of the aluminumelectric wires having been press-fitted. In the state of the first slitbeing opened, when the second one of the aluminum electric wires ispress-fitted, the aluminum electric wire is sometimes in insufficientcontact with the contact surfaces. As a result, the insulating coatingthat covers the core wire is not sufficiently removed. The insufficientremoval of the insulating coating of the aluminum electric wireincreases the contact resistance between the core wire and the contactsurfaces. The contact resistance increases to exceed the allowablevalue, resulting in a poor electrical connection.

Specific Example

By contrast, as shown in FIG. 11, upon press-fitting of the first one ofaluminum electric wire 17, connection terminal 10A having temporarilyholding part 21 according to the first embodiment holds the first one ofaluminum electric wire 17 at temporarily holding part 21. At that time,first slit 13 becomes in the state of being not widely opened because ofelasticity and so on.

After that, as shown in FIG. 12, the second one of aluminum electricwire 117 is press-fitted into first slit 13. When press-fitting thesecond one of aluminum electric wire 117, the second one is pressedtogether with the first one of aluminum electric wire 17 held attemporarily holding part 21, which thereby press-fits two aluminumelectric wires 17 and 117 toward first tip 16 of first slit 13.

As shown in FIG. 13, the simultaneous press-fitting of two aluminumelectric wires 17 and 117 allows a stable and appropriate removal ofinsulating coatings 17B of aluminum electric wires 17 and 117 by contactsurfaces 14 included in first slit 13 that has maintained apredetermined slit width.

As a result, core wires 17A of two aluminum electric wires 17 and 117can be in contact with contact surfaces 14 in the range corresponding tothe appropriate contact resistance.

Second Exemplary Embodiment

A connection device according to a second embodiment of the presentinvention will be described, with reference to FIGS. 14 to 27.

FIG. 14 is a perspective view of the connection device according to thesecond embodiment of the invention. FIG. 15 is a perspective view of aprincipal part of the connection device according to the secondembodiment of the invention. Using FIGS. 14 and 15, the general outlineof the connection device according to the second embodiment of theinvention will be described.

FIG. 16 is a cross-sectional perspective view of a cavity which isincluded in the connection device according to the second embodiment ofthe invention. FIG. 17 is an elevational view of the cavity that isincluded in the connection device according to the second embodiment ofthe invention. FIG. 18 is a cross-sectional perspective view of aprincipal part of the connection device according to the secondembodiment of the invention. FIG. 19 is another cross-sectionalperspective view of the principal part of the connection deviceaccording to the second embodiment of the invention. FIG. 20 is across-sectional view taken along line 20-20 in FIG. 19. Using FIGS. 16to 20, a procedure for assembling the connection device according to thesecond embodiment of the invention will be described.

Note, however, that the direction in which the connection device isinserted into the cavity is not limited to that in the followingdescriptions.

The connection device according to the second embodiment of theinvention is used for an aluminum electric wire which includes a corewire and an insulating coating that covers the outer peripheral surfaceof the core wire.

As shown in FIGS. 14 and 15, connection device 30 according to thesecond embodiment of the invention includes connection terminals 10 andholding part 32 equipped with cavities 31 into which connectionterminals 10 are inserted.

For connection terminals 10, the descriptions thereof in the firstembodiment are cited herein. Note that, needless to say, connectionterminals 10 can be replaced by connection terminals 10A in thefollowing descriptions.

As shown in FIGS. 16 and 17, each of cavities 31 includes wall surface33 and second slit 34. Wall surface 33 surrounds at least pinchingplates of the connection terminal to be inserted. Second slit 34 isformed such that, in wall surface 33, second open end 35 is located inone side of the slit while second tip 36 is located in the other side,at a location facing the first slit included in the connection terminalto be inserted. In second slit 34, second open end 35 is larger in aslit width than second tip 36. That is, width t1 of the second tip issmaller than width t2 of the second open end.

Further details of this are as follows.

The holding part can be formed with a resin. The resin may bepolybutylene terephthalate (referred to as PBT, hereinafter), a liquidcrystal polymer (referred to as an LCP, hereinafter), or the like.

In particular, the PBT resin is advantageous in view of heat resistanceand electric characteristics. The PBT resin is less expensive than theLCP. A specific example of the PBT resin is a PBT resin 1101G-30manufactured by Toray Industries, Inc.

As shown in FIGS. 14 and 15, holding part 32 includes cavities 31. Eachof cavities 31 supports connection terminal 10. As shown in FIG. 15, incavity 31, pinching plates 12 included in connection terminal 10 areinserted into a space surrounded by wall surface 33. The spacesurrounded by wall surface 33 holds pinching plates 12, which allowsconnection terminal 10 to be supported by cavity 31. Note, however, thatcavity 31 may be configured such that wall surface 33 further surroundstab part 11 as long as cavity 31 can support connection terminal 10.

As shown in FIG. 16, wall surface 33 includes second slit 34. In secondslit 34, second open end 35 is located in the opening 37 side of cavity31. Second slit 34 is of a taper shape in which second open end 35 islarger in a slit width than second tip 36. Cavity 31 includes third slit38 in wall surface 33A that faces wall surface 33 having second slit 34.Third slit 38 may be not of the taper shape, but of a straight shape inwhich third tip 39 is the same in a slit width as third open end 40.Alternatively, third slit 38 may be of a taper shape larger in siltwidth than second slit 34.

As long as second slit 34 included in wall surface 33 has the tapershape, the aluminum electric wire to be connected is held by any part ofsecond slit 34 depending on the wire diameter. Accordingly, the use ofthe connection device including cavities 31 with one type of the shapeallows connections of other electric wires than the aluminum electricwire. That is, this provides commonality of the connection devices.

The cavity according to the second embodiment includes an electric wiremount in the inside of the space surrounded by the wall surface. Asshown in FIG. 22, electric wire mount 41 disposed on the bottom surfaceof each of cavities 31 is located on line 47 that connects second slit34 and third slit 38. As shown in FIG. 17, electric wire mount 41 ispreferably the same in height as second tip 36.

In the cavity with the configuration described above, the aluminumelectric wire is disposed. As shown in FIG. 18, aluminum electric wire17 is inserted into second slit 34 included in wall surface 33.Thus-inserted aluminum electric wire 17 is held by second slit 34 withthe taper shape. When aluminum electric wire 17 being held by secondslit 34, connection terminal 10 is inserted from the opening 37 side ofcavity 31, as indicated by the arrow in FIG. 18. Connection terminal 10is inserted into cavity 31 such that first slit 13 included in pinchingplate 12 of connection terminal 10 faces second slit 34 included in wallsurface 33 of cavity 31. Upon the insertion of connection terminal 10into cavity 31, aluminum electric wire 17 held by second slit 34 is thenintroduced into first slit 13 included in pinching plate 12. Followingthe insertion of connection terminal 10 into cavity 31, aluminumelectric wire 17 is pushed downward in FIG. 18. Then, aluminum electricwire 17 is held by second slit 34 and simultaneously arrives on electricwire mount 41. Moreover, as shown in FIGS. 19 and 20, when connectionterminal 10 is pushed into cavity 31, pinching plates 12 included inconnection terminal 10 are held in the space surrounded by wall surface33 included in cavity 31.

Note that, in FIG. 18, the pinching plates (inner pinching plates 12B)disposed in the inside of connection terminal 10 is omitted from thedescriptions for the sake of clear understanding of connection terminal10. Hereinafter, the same omission will be made in the followingdescriptions.

As shown in FIGS. 19 and 20, aluminum electric wire 17 is restrained bysecond slit 34 from being out of position in transverse direction 42indicated by the arrow in the figure. Aluminum electric wire 17 isrestrained by electric wire mount 41 from being out of position inheight direction 43 indicated by the arrow in the figure. Becauseelectric wire mount 41 is the same in height as second tip 36, aluminumelectric wire 17 can undergo a stable removal of the insulating coatingby contact surfaces 14 included in pinching plates 12. At that time,third slit 38 does not hold aluminum electric wire 17. Therefore, duringthe insertion of connection terminal 10 into cavity 31, aluminumelectric wire 17 is not subjected to unnecessary forces from third slit38. Consequently, it is possible to prevent aluminum electric wire 17from being broken due to the insertion of connection terminal 10 intocavity 31.

As a result, aluminum electric wire 17 and connection terminal 10 areconnected with each other with a stable contact resistance. Aluminumelectric wire 17 and connection terminal 10 are connected with eachother with high reliability. Mounting work of aluminum electric wire 17can be performed in a state in which the wire is held by second slit 34.This improves workability of the mounting.

Next, configurations featuring more outstanding advantages will bedescribed.

FIG. 21 is a plan view of a connection terminal which is included in theconnection device according to the second embodiment of the presentinvention. FIG. 22 is a plan view of a cavity which is included in theconnection device according to the second embodiment of the invention.FIG. 23 is a plan view illustrating a state where the connectionterminal is inserted into the cavity included in the connection deviceaccording to the second embodiment of the invention. Using FIGS. 21 to23, descriptions will be made regarding a configuration, which featuresparticularly outstanding functional advantages, of the connection deviceaccording to the second embodiment of the invention.

FIG. 24 is a perspective view of another connection terminal which isincluded in the connection device according to the second embodiment ofthe invention. FIG. 25 is a plan view of another cavity which isincluded in the connection device according to the second embodiment ofthe invention. FIG. 26 is a perspective view of a different connectionterminal which is included in the connection device according to thesecond embodiment of the invention. FIG. 27 is a plan view of adifferent cavity which is included in the connection device according tothe second embodiment of the invention. Using FIGS. 24 to 27,descriptions will be made regarding another configuration, whichfeatures particularly outstanding functional advantages, of theconnection device according to the second embodiment of the invention.

In the connection device according to the second embodiment of theinvention, each of the pinching plates includes a fitting part while thecavity includes a to-be-fitted part. The pinching plate includes thefitting part in the direction orthogonal to the direction in which thefirst slit opens from the first tip toward the first open end. Thecavity includes the to-be-fitted part that fits onto the fitting part.

The specific configuration is as follows. The fitting part is aprojection which protrudes from a side surface of the pinching platetoward the outside. The to-be-fitted part is a recess, which fits ontothe projection, in the inner wall surface of the cavity.

Moreover, detailed descriptions will be made using FIGS. 21 to 23.

As shown in FIG. 21, pinching plates 12 held by the wall surface of thecavity include projections 45 that protrude from the side surfaces ofpinching plates 12 toward the outside. Projections 45 are disposed atthe four corners of outer pinching plates 12A that form the outer shell.

As shown in FIG. 22, in inner wall surface 33B, i.e. wall surface 33 ofcavity 31 into which pinching plates 12 are inserted, recesses 46 aredisposed at locations corresponding to projections 45. Projections 45are fitted into recesses 46.

Descriptions will be made regarding functional advantages of theconnection device with the configuration described above.

Vibrations and temperature variations are applied to the connectiondevice to which the aluminum electric wire and the connection terminalare connected. If there is some degree of freedom in the insertionposition of the connection terminal in the cavity, the connectionterminal can move relative to the cavity due to influences of theapplied vibrations and temperature variations. Its moving distances aresmall; however, the influences thereof are accumulated when theconnection terminal is subjected to strong vibrations and temperaturevariations over a long period of time. The accumulation of the smallmovements will accelerate the creep deformation of the aluminum electricwire. The accelerated creep deformation causes stress relaxation of thealuminum electric wire. As a result, the contact resistance increasesbetween the aluminum electric wire and the connection terminal.Alternatively, a decrease in wire strength of the aluminum electric wirecauses the aluminum electric wire to be broken.

Hence, connection device 30A according to the second embodiment is usedas shown in FIG. 23. Upon insertion of connection terminal 10 intocavity 31, projections 45 included in pinching plates 12 are fitted intorecesses 46 in wall surface 33. The fitting between projections 45included in pinching plates 12 and recesses 46 in wall surface 33 causesconnection terminal 10 to be fixed in cavity 31.

As a result, it is possible to prevent connection terminal 10 frommoving relative to cavity 31 even when the vibrations and temperaturevariations are applied to connection device 30A.

Incidentally, the direction in which connection terminal 10 movesrelative to cavity 31 includes rotational directions, a fore-and-aftdirection, and a side-to-side linear direction depending on the mode ofusage of connection device 30A.

As shown in a fourth embodiment to be described later, in the case wherethe connection device according to the second embodiment is used in acompressor, it is possible to prevent the movement in the rotationaldirections.

Note, however, that both the fitting parts included in the pinchingplates and the to-be-fitted parts included in the cavity may employother respective shapes, as long as the connection device can beprevented from moving relative to the cavity.

For example, as shown in FIGS. 24 and 25, the recesses and theprojections may be interchanged therebetween in comparison with theconnection device shown in FIG. 18. That is, pinching plates 12Cincluded in connection terminal 10B include recesses 49 serving as thefitting parts. Cavity 31A includes projections 50 serving as theto-be-fitted parts.

Alternatively, as shown in FIGS. 26 and 27, pinching plates 12D includedin connection terminal 10C include projections 45A, serving as thefitting parts, which are bended along direction 23 in which the pinchingplates are arranged. Cavity 31B includes recesses 46A, serving as theto-be-fitted parts, in inner wall surface 33C in which second slit 34and third slit 38 are formed.

Moreover, it does not matter what the numbers of the fitting parts andthe to-be-fitted parts are as long as they can prevent the connectionterminal from moving relative to the cavity. For example, only three ofthe fitting parts may be disposed for the outer pinching plates.Alternatively, only two of the fitting parts may be diagonally disposedfor the outer pinching plates.

As can be seen from the above descriptions, the use of the connectionterminal according to the second embodiment allows the suppression ofthe creep deformation of the aluminum electric wire that is used underthe difficult conditions in terms of vibration and temperaturevariation. The suppression of the creep deformation allows theprevention of the occurrence of the stress relaxation. As a result, itis possible to provide the connection device in which the aluminumelectric wire and the connection terminal are connected to each otherwith high reliability.

Third Exemplary Embodiment

A method for manufacturing the connection devices shown in the secondembodiment of the present invention will be described using FIGS. 28 to33. Note that, in a part of the description, the drawings used in thesecond embodiment are cited herein.

FIG. 28 is a flowchart illustrating the method for manufacturing aconnection device according to a third embodiment of the invention. FIG.29 is an illustrative view of an assembly operation of the connectiondevice according to the third embodiment of the invention. Using FIGS.28 and 29, the method for manufacturing the connection device accordingto the third embodiment of the invention will be described.

FIG. 30 is a flowchart illustrating another method for manufacturing theconnection device according to the third embodiment of the invention.FIG. 31 is a cross-sectional perspective view of a principal part of theconnection device according to the third embodiment of the invention.FIG. 32 is another cross-sectional perspective view of the principalpart of the connection device according to the third embodiment of theinvention. Using FIGS. 30 to 32, the another method for manufacturingthe connection device according to the third embodiment of the inventionwill be described.

FIG. 33 is a characteristic graph illustrating characteristics of anincremental quantity of contact resistance with respect to the number ofinsertion-removal cycles of a flat connection terminal into and from theconnection device according to the third embodiment of the invention,with the flat connection terminal fitting into the connection device.

The method for manufacturing the connection device according to thethird embodiment of the invention includes a process of inserting theconnection terminal into a cavity. In the inserting process, theinsertion speed of the connection terminal into the cavity is 40 mm/secto 200 mm/sec.

Moreover, in the inserting process, an insertion angle is within ±10°.The insertion angle is formed by the center line of the connectionterminal along an insertion direction of the connection terminal whichis inserted into the cavity and the center line of the cavity along aninsertion direction of the cavity into which the connection terminal isinserted.

Furthermore, the method includes a process of bending the tab partrelative to the pinching plates in the connection terminal. Then, afterthe bending process, an inserting process is performed.

Details of this are as follows.

As shown in FIG. 28, the manufacture of the connection device shown inthe second embodiment of the present invention is started by preparingthe connection terminals and the holding parts (S1, S2). The processesdesignated by S1 and S2 in FIG. 28 may be performed in in-housemanufacturing. Alternatively, any of the connection terminals andholding parts may be purchased from other manufacturers.

As shown in FIG. 18, in cavity 31 of the thus-prepared holding part,aluminum electric wire 17 is disposed (S3). Aluminum electric wire 17 isdisposed to pass through both second slit 34 and third slit 38 that areincluded in cavity 31.

After that, as indicated by the arrow in FIG. 18, thus-preparedconnection terminal 10 is inserted into cavity 31 of the holding part(S4).

At that time, the insertion speed at which connection terminal 10 isinserted into cavity 31 is set to be 40 mm/sec to 200 mm/sec. By settingthe insertion speed to be 40 mm/sec to 200 mm/sec, loads on aluminumelectric wire 17 being press-fitted into first slits 13 can be reduced.

That is, when inserting connection terminal 10 into cavity 31, theinsulating coating applied to aluminum electric wire 17 is removed bycontact surfaces 14 included in pinching plates 12. Moreover, aluminumelectric wire 17 is press-fitted into first slits 13 such that the corewire comes in contact with contact surfaces 14 to exhibit apredetermined contact resistance. Accordingly, when inserting connectionterminal 10 into cavity 31, these factors need to be taken intoconsideration in inserting connection terminal 10.

The result of a verification test of this is shown in Table 2.

TABLE 2 Relation between insertion speeds and states of insertion wheninserting the connection terminals into the cavities Insertion speed(mm/sec) 10 20 30 40 50 70 100 200 300 State of insertion X X X ◯ ◯ ◯ ◯◯ X ◯: good pressure contact X: broken wire or twisted terminal

The verification test has shown that the insertion speeds slower than 40mm/sec result in broken aluminum electric wires 17. This appears to bebecause so-called moving-together phenomenon occurs in which aluminumelectric wire 17 moves together with connection terminal 10 that isinserted into cavities 31.

Moreover, the insertion speeds faster than 200 mm/sec result in failuresof twisted connection terminals 10 or broken cavities 31.

As can be seen from the above result, with the insertion speed ranging40 mm/sec to 200 mm/sec, it is possible to suppress the occurrence ofthe failures in the manufacturing process in which connection terminal10 is inserted into cavity 31.

Moreover, as shown in FIG. 29, let β be the insertion angle wheninserting connection terminal 10 into cavity 31. The insertion angle isformed by center line 60 of connection terminal 10 along the insertiondirection of connection terminal 10 which is inserted into cavity 31 andcenter line 61 of cavity 31 along the insertion direction of cavity 31into which connection terminal 10 is inserted. By setting insertionangle β to be within ±10°, it is possible to prevent the occurrence ofthe deformation of connection terminal 10 when inserting connectionterminal 10 into cavity 31.

It is considered that the deformation of connection terminal 10depending on the insertion angle is considered to be factors responsiblefor a state of twisting between cavity 31 and connection terminal 10.The state of twisting is considered to accelerate the creep deformationwhen the connection device is used under difficult conditions.

Consequently, the restriction of the insertion angle allows thesuppression of the occurrence of the creep deformation in the aluminumelectric wire.

Therefore, as shown in the fourth embodiment to be described later, theconnection device into which the connection terminals are press-fittedis used in a compressor. It is possible to suppress the acceleration ofthe creep deformation even when the connection device described above isused inside the compressor under difficult conditions in terms ofvibration and temperature variation. The suppression of the accelerationof the creep deformation allows the prevention of the stress relaxationof the aluminum electric wire. As a result, it is possible to providethe connection device in which the aluminum electric wire and theconnection terminal are connected to each other with high reliability.

Alternatively, as shown in FIGS. 18 and 30, the connection terminal isbent (S5) after aluminum electric wire 17 has been disposed (S3) incavity 31 of thus-prepared holding part 32.

As shown in FIGS. 30 and 31, thus-bent connection terminal 10D isinserted into cavity 31 of the holding part (S4).

For example, there are sometimes cases where the connection device issubjected to a height limit when used in such as the compressor shown inthe fourth embodiment.

In the cases, the flat connection terminal to be fitted into theconnection terminal is sometimes formed to be a flag-shaped terminal.Moreover, when subjected to the height limit, there is no choice but tobend the connection terminal at a boundary between the tab part and thepinching plates thereof. Therefore, as shown in FIG. 31, connectionterminal 10D is bent in advance. Thus-bent connection terminal 10D isinserted into cavity 31. Employing such the manufacturing method makesit possible to suppress the deformation of connection terminal 10D.

Consequently, it is possible to suppress poor contact due to thedeformation of the connection terminal. As a result, there is nooccurrence of heat generation or the like caused by the poor contact atthe connecting portions between the connection terminal and the aluminumelectric wire, the connection terminal and the flat connection terminal,the connection terminal and the flag-shaped terminal, and the like.

Table 3 shows a relation between contact resistance and the bending ofthe connection terminal.

TABLE 3 Variations in contact resistance with respect to the bending ofthe connection terminals Conditions No-bending Pre-bending Post-bendingContact resistance 0.4 0.4 1.0 (mΩ)

“No-bending” referred in Table 3 is the states of connection terminals10 and 10A shown in the first and second embodiments, respectively.“Pre-bending” is the state of connection terminal 10D that is formed inadvance by bending process S5 described in the third embodiment.“Post-bending” is the state of connection terminal 10E shown in FIG. 32that is formed by bending tab part 11 after connection terminal 10 hasbeen inserted into cavity 31.

As can be seen from FIG. 3, “pre-bended” connection terminal 10D showsno difference in contact resistance from “no-bended” connection terminal10. On the other hand, “post-bended” connection terminal 10E shows 1.5times higher contact resistance than “no-bended” connection terminal 10.

This is thought to be due to an unnecessary deformation of connectionterminal 10E, which is caused by bending tab part 11 without directholding of the pinching plates 12 side when bending connection terminal10E.

Moreover, variations in contact resistance of the flag-shaped terminalhave been verified, with the terminal being subjected toinsertion-removal cycles, i.e. repeatedly inserting and removing theterminal into and from tab part 11.

The result is shown in FIG. 33. As shown in FIG. 33, it has beenverified that the one-time removal causes a large increase in contactresistance.

In other words, the pre-bending of the connection terminal yields astable shape of the connection terminal. It is the pre-bended connectionterminal that is inserted into the cavity. Therefore, the portionconnected to the pre-bended connection terminal will provide the stablecontact resistance. As a result, it is possible to provide theconnection device in which the aluminum electric wire and the connectionterminal are connected to each other with high reliability.

Note, however, that the direction in which the tab part is bent relativeto the connection terminal is optionally set in accordance withsituations of such as the flag-shaped terminal to be fitted. Thedirection in which the tab part is bent relative to the connectionterminal is not limited to that in the above descriptions.

Fourth Exemplary Embodiment

A fourth embodiment of the present invention will be described, withreference to the accompanying drawings.

FIG. 34 is a perspective assembly view of a motor according to thefourth embodiment of the invention. FIG. 35 is a perspective assemblyview of a stator which is included in the motor according to the fourthembodiment of the invention. FIG. 36 is a perspective assembly view ofanother connection device which is included in the motor according tothe fourth embodiment of the invention.

The motor using the connection device shown in the second embodiment ofthe invention will be described using FIGS. 34 to 36.

FIG. 34 shows an example of the motor according to the fourth embodimentof the invention. The motor according to the fourth embodiment of theinvention is a brushless motor. The aspect of the motor according to thefourth embodiment of the invention is applicable to motors with otherconfigurations.

Motor 70 includes rotary shaft 71, a pair of shaft bearings 72, rotor73, and stator 74.

The pair of shaft bearings 72 are attached to rotary shaft 71 so as tosandwich rotor 73. Rotor 73 includes magnets 75 at the outer peripherythereof. Rotor 73 is inserted into the inside of stator 74 such that thestator 74 faces magnets 75 included at the outer periphery of the rotor.

As shown in FIG. 35, stator 74 includes holding part 32, core 76, andfixing member 77. Core 76 is fitted to and fixed between holding part 32and fixing member 77. A winding is wound on each of teeth 78 included instator 74. One end of the winding is connected to connection terminal 10that is inserted into each of cavities 31 included in holding part 32.

In this way, the motor according to the fourth embodiment of the presentinvention is configured.

Note that, as shown in FIG. 36, in the motor according to the fourthembodiment of the invention, connection device 30B may be formed ofholding part 32A that is composed of only a principal part thereof. Inthis case, an insulating film or the like may be employed for insulationof, such as, core 76 shown in FIG. 35.

The motor described above is used in a compressor shown in FIG. 37.

FIG. 37 is a cross-sectional view of the compressor according to thefourth embodiment of the invention. FIG. 38 is a cross-sectional view ofa blower according to the fourth embodiment of the invention.

In addition, the compressor using the motor will be described using FIG.37. Likewise, the blower using the motor will be described using FIG.38.

Compressor 80 includes motor 70 and compression part 82 in case 81thereof. Case 81 is equipped with an intake pipe and a discharge pipe.

A coolant suctioned into case 81 via the intake pipe is conveyed intocompression part 82. Compression part 82 is driven by motor 70.Compression part 82 is driven to compress the coolant. The compressedcoolant is discharged from the discharge pipe into a refrigerationcycle.

Like this, the motor is used in the blower shown in FIG. 38.

Blower 90 includes motor 70 in case 91 thereof. A fan is attached torotary shaft 71. The rotation of rotor 73 causes a rotation of the fanattached to rotary shaft 71.

The motor according to the fourth embodiment of the invention isapplicable to a wide range of applications. Among the applications, thecompressor is used under difficult conditions in terms of vibration andtemperature variation and the blower is used under difficult conditionsin terms of vibration.

However, as described in detail in the second embodiment, the use of theconnection device according to the second embodiment of the inventionallows the suppression of the movement of the connection terminalrelative to the cavity even when being used under the difficultconditions in terms of vibration and temperature variation.

Accordingly, the creep deformation occurring in the aluminum electricwire is suppressed. The suppression of the creep deformation, in turn,allows the prevention of the stress relaxation. As a result, it ispossible to provide the motor in which the aluminum electric wire andthe connection terminal are connected to each other with highreliability. Moreover, it is possible to provide the compressor usingthe motor and the blower using the motor.

Advantages of the compressor and the blower according to the fourthembodiment of the invention were examined, in comparison withcomparative ones using conventional connection terminals. The resultwill be described using Table 4, FIG. 39, and FIG. 40.

The comparison was made through a thermal shock test and a vibrationtest. Table 4 shows combinations of the test objects. After each of thetests had been conducted, variations in contact resistance were examinedand evaluated.

Comparison of combinations of connection terminals and electric wirematerials

TABLE 4 Comparison of combinations of connection terminal materials andelectric wire materials Comparative Comparative Items Example 1 Example1 Example 2 Connection Terminal of the Conventional Conventionalterminal embodiment terminal terminal Electric wire Aluminum AluminumCopper material

FIG. 39 is a characteristic graph that illustrates a relation betweenthe contact resistance and the number of cycles of the thermal shocktest that compares the connection device according to the fourthembodiment of the invention with the comparative ones. FIG. 40 is acharacteristic graph that illustrates the contact resistance before andafter the vibration test that compares the connection device accordingto the fourth embodiment of the invention with the comparative ones.

Using FIGS. 39 and 40, the result of the comparison will be describedbetween the example according to the embodiment of the invention and theconventional ones.

The thermal shock test was carried out with the following conditions.The ambient temperature was varied from −40° C. to 120° C. One cycleconsisted of states, i.e. the state where the ambient temperature of−40° C. was kept for 30 minutes and the state where the ambienttemperature of 120° C. was kept for 30 minutes. The cycle was repeated2000 times, i.e. 2000 cycles.

The vibration test was carried out with the following conditions. Thevibration frequency was in a range from 10 Hz to 55 Hz. The linear sweeptime was one minute. The amplitude was 1.6 mm, with a current of 0.1 Aflowing through the test objects. The vibration was made in threedirections, i.e. fore-and-aft, up-and-down, and side-to-side directions.

From Table 4 and FIG. 39, the result of the thermal shock test allows toconfirm that a remarkable increase in contact resistance appears forComparative Example 1 that uses the combination of the conventionalconnection terminal and the aluminum electric wire. The combinationhaving been thought to involve the subject to be solved.

On the other hand, the thermal shock test allows to confirm that Example1 exhibits the contact resistance comparable to or smaller than that ofthe combination of the conventional connection terminal and the copperelectric wire (Comparative Example 2).

Moreover, from Table 4 and FIG. 40, the result of the vibration testallows to confirm that a remarkable increase in contact resistanceappears for Comparative Example 1 that uses the combination of theconventional connection terminal and the aluminum electric wire, wherethe combination have been thought to involve the subject to be solved.

On the other hand, the vibration test has shown that Example 1 exhibitsthe contact resistance comparable to or smaller than that of thecombination of the conventional connection terminal and the copperelectric wire (Comparative Example 2).

As can be seen from the above results, the use of each of theembodiments of the present invention allows the following functionaladvantages.

That is, the aluminum electric wire can be used, which allows areduction in weight of electrical apparatus.

Further, it is possible to prevent the occurrence of the stressrelaxation by suppressing the creep deformation, even in the use of thealuminum electric wire under difficult conditions in terms of vibrationand temperature variation. The occurrence of the stress relaxation hasbeen a matter of concern for the aluminum electric wire. That is, inaccordance with each of the embodiments of the present invention, it ispossible to maintain the contact resistance comparable to that of thecombination of the conventional copper electric wire and theconventional connection terminal. Therefore, it is possible to avoidfailures including heat generation due to the increase in contactresistance.

Consequently, this allows the same usage/handling as that of theconventional combination of copper electric wires and conventionalconnection terminals.

INDUSTRIAL APPLICABILITY

The connection terminal according to the present invention used for thealuminum electric wire, the connection device including the connectionterminal, the method for manufacturing the connection device, the motorusing the connection device, and the compressor using the motor and theblower using the motor, are applicable to the fields of application ofelectrical apparatus, including compressors and blowers, which employsconventional copper electric wires.

REFERENCE MARKS IN THE DRAWINGS

-   -   10, 10A, 10B, 10C, 10D, 10E connection terminal    -   11 tab part    -   12, 12C, 12D pinching plate    -   12A outer pinching plate    -   12B inner pinching plate    -   13 first slit    -   14, 14A, 14B contact surface    -   15 first open end    -   16 first tip    -   17, 117 aluminum electric wire    -   17A core wire    -   17B insulating coating    -   18 effective contact surface    -   19 contact point    -   21 temporarily holding part    -   22 tapered part    -   23 direction in which pinching plates are arranged    -   24 contact-resistance increasing region    -   25 wire-strength decreasing region    -   30, 30A, 30B connection device    -   31, 31A, 31B cavity    -   32, 32A holding part    -   33, 33A wall surface    -   33B, 33C inner wall surface    -   34 second slit    -   35 second open end    -   36 second tip    -   37 opening    -   38 third slit    -   39 third tip    -   40 third open end    -   41 electric wire mount    -   42 transverse direction    -   43 height direction    -   45, 45A projection (fitting part)    -   46, 46A recess (to-be-fitted part)    -   47 line    -   49 recess (fitting part)    -   50 projection (to-be-fitted part)    -   60, 61 center line    -   70 motor    -   71 rotary shaft    -   72 shaft bearing    -   73 rotor    -   74 stator    -   75 magnet    -   76 core    -   77 fixing member    -   78 teeth    -   80 compressor    -   81, 91 case    -   82 compression part    -   90 blower

The invention claimed is:
 1. A connection terminal unit comprising: aconnection terminal; and an aluminum electric wire comprising a corewire and an insulating coating for covering an outer peripheral surfaceof the core wire, wherein the connection terminal comprises a tab part;and at least four pinching plates for holding the aluminum electricwire, wherein each of the pinching plates includes a first slit having afirst open end located in one side and having a first tip located in another side, the aluminum electric wire being press-fitted into the firstslit, and a contact surface in contact with the aluminum electric wirepress-fitted into the first slit, and wherein a total contact areabetween each the contact surface of the contact surfaces at least fourpinching plates and the core wire is an area of 100% to 200% of a radialcross-sectional area of the core wire, the total contact area being atotal area of effective contact surfaces at which the contact surface isin contact, relative to the radial cross-sectional area of the corewire, and wherein the first slit includes a temporarily holding part fortemporarily holding the aluminum electric wire when the aluminumelectric wire is press-fitted.
 2. The connection terminal unit accordingto claim 1, wherein the contact surface includes an inclination anglefrom 15° to 75° relative to a direction of arranging the at least fourpinching plates.
 3. The connection terminal unit according to claim 1,wherein the first slit includes a temporarily holding part fortemporarily holding the aluminum electric wire when the aluminumelectric wire is press-fitted.
 4. A connection terminal used for analuminum electric wire including a core wire, and an insulating coatingfor covering an outer peripheral surface of the core wire, theconnection terminal comprising: a tab part; and at least four pinchingplatesfor holding the aluminum electric wire, wherein each of thepinching plates includes include a first slit having a first open endlocated in one side and having a first tip located in an other side, thealuminum electric wire being press-fitted into the first slit, and acontact surface in contact with the aluminum electric wire press-fittedinto the first slit, wherein a total contact area between each thecontact surface of the contact surfaces at least four pinching platesand the core wire is an area of 100% to 200% of a radial cross-sectionalarea of the core wire, when the at least four pinching plates hold thealuminum electric wire, and the total contact area being a total area ofeffective contact surfaces at which the contact surface is in contact,relative to the radial cross-sectional area of the core wire, whereinthe first slit includes a temporarily holding part for temporarilyholding the aluminum electric wire when the aluminum electric wire ispress-fitted, and the temporarily holding part includes a recessed partthat is formed of taper shaped parts in the first slit.
 5. Theconnection terminal according to claim 4, wherein the contact surfaceincludes an inclination angle from 15° to 75° relative to a direction ofarranging the at least four pinching plates.
 6. The connection terminalaccording to claim 4, wherein the temporarily holding part is locatedcloser to the first open end than the contact surface the recessed partincludes two recessed parts, the two recessed parts facing each other inthe first slit, each of the two recessed parts is formed of two tapershaped parts, and the taper shaped parts are configured to be locatedaround the aluminum electric wire press-fitted into the first slit tohold the aluminum electric wire.
 7. A connection terminal unitcomprising: a connection terminal; and an aluminum electric wirecomprising a core wire and an insulating coating for covering an outerperipheral surface of the core wire, wherein the connection terminalcomprises a tab part; and at least four pinching plates for holding thealuminum electric wire, wherein each of the pinching plates includes afirst slit having a first open end located in one side and having afirst tip located in an other side, the aluminum electric wire beingpress-fitted into the first slit, and a contact surface in contact withthe aluminum electric wire press-fitted into the first slit, and whereina total contact area between the contact surface of the at least fourpinching plates and the core wire is an area of 100% to 200% of a radialcross-sectional area of the core wire, the total contact area being atotal area of effective contact surfaces at which the contact surface isin contact, relative to the radial cross-sectional area of the corewire, and wherein the first slit includes a temporarily holding part fortemporarily holding the aluminum electric wire when the aluminumelectric wire is press-fitted, the temporarily holding part is locatedcloser to the first open end than the contact surface, the temporarilyholding part includes two recessed parts in the first slit, the tworecessed parts facing each other in the first slit, each of the tworecessed parts is formed of two taper shaped parts, and the taper shapedparts are configured to be located around the aluminum electric wirepress-fitted into the first slit to hold the aluminum electric wire. 8.The connection terminal unit according to claim 7, wherein the contactsurface includes an inclination angle from 15° to 75° relative to adirection of arranging the at least four pinching plates.